Lamellar stacking split by in-membrane clustering of bulky glycolipids

We developed a simple model to investigate the effect of lipid clustering on the local interlayer distance in a cluster of interacting lamellae. The model, based on nonequilibrium thermodynamics and linear stability theories, explores the early stages of the lamella-lamella phase separation process where the lateral diffusion is much faster than the interlamellar lipid exchange. Results indicate, in the early stages, the presence of locally distorted regions with a higher concentration of one lipid component and an anomalous repeat distance. Experimental cases are presented, consisting of multilamellar-oriented depositions of phospholipids containing minority amounts of ganglioside or sphingomyelin under a low-hydration condition. The minority components are known to form domains within the phospholipid bilayer matrix. The low water content inhibits the lipid exchange among nearby lamellae and strengthens lamella-lamella interaction, allowing for a straightforward comparison with the model. Small-angle and wide-angle neutron diffraction experiments were performed in order to detect interlayer distances and local chain order, respectively. Lamellar stacking splitting has been observed for the ganglioside-containing lamellae, induced by in-phase lipid clustering. In excess water and after long equilibration times, these local structures may further evolve, leading to coexisting lamellar phases with different lipid compositions and interlayer distances.

Structure of self-organized multilayer nanoparticles for drug delivery

The combined use of cryo-TEM, dynamic light scattering, and small-angle X-ray and neutron scattering techniques allows a detailed structural model of complex pharmaceutical preparations of soybean lecithin/chitosan nanoparticles used as drug vectors to be worked out. Charge-driven self-organization of the lipid(-)/polysaccharide(+) vesicles occurs during rapid injection, under mechanical stirring, of an ethanol solution of soybean lecithin into a chitosan aqueous solution. We conclude that beyond the charge inversion region of the phase diagram, i.e., entering the redissolution region, the initial stages of particle formation are likely to be affected by a re-entrant condensation effect at the nanoscale. This behavior resembles that at the mesoscale which is well-known for polyion/amphiphile systems. Close to the boundary of the charge inversion region, nanoparticle formation occurs under a maximum condensation condition at the nanoscale and the complexation-aggregation process is driven toward a maximum multilamellarity. Interestingly, the formulation that maximizes vesicle multilamellarity corresponds to that displaying the highest drug loading efficiency.

Protecting effect of vitamin E supplementation on submaximal exercise-induced oxidative stress in sedentary dogs as assessed by erythrocyte membrane fluidity and paraoxonase-1 activity

The aim of this placebo-controlled study was to investigate the effects of oral vitamin E supplementation for 10 weeks on exercise-induced oxidative damage in untrained dogs. Eight dogs were randomly assigned to a supplementation (n=4) or control (n=4) group and underwent two isolated submaximal exercise sessions, 10 weeks apart. Blood was collected during each session to measure erythrocyte membrane fluidity (EMF), paraoxonase-1 (PON1) activity, plasma malondialdehyde (MDA) and vitamin E concentrations. These biomarkers were measured in venous blood samples collected before (t(0)), just after (t, EMF only) and 1d (t+1d) and 7d (t+7d) after the dogs ran on a treadmill. Prior to vitamin E supplementation, exercise induced a significant decrease in PON1 activity, EMF, vitamin E concentration and a significant increase in MDA concentration at t+1d. After a 10 week vitamin E supplementation period, these exercise-induced changes in PON1 activity, EMF and MDA concentration were still significant in the control group, but not in the supplemented group. These results suggested that vitamin E supplementation had a protective effect on submaximal exercise-induced oxidative damage in sedentary dogs.

Adeno-tonsillar surgery in Italy

Indications to surgery for adeno-tonsillar inflammatory disorders and analysis of the effectiveness of surgical treatment, compared with watchful waiting strategy, continue to be the subject of scientific debate. The present investigation focuses on the surgical activity of 14 Italian Otorhinolaryngological Units between 1999 and 2004. Surgical interventions (adeno-tonsillectomy, adenoidectomy, tonsillectomy) on 26915 children (age range: 2-11 years) were considered. Data on adeno-tonsillar interventions were analysed in relation to other interventions of ENT interest, performed in the same units and in the same period. Adeno-tonsillar interventions accounted for 35.4% of all operations of ENT interest. Adeno-tonsillectomy accounted for 56.6% of overall adeno-tonsillar operations, adenoidectomy 31.6%, tonsillectomy 11.8%. The percentage for the three interventions was homogeneous in the period of the study and in the recruited units. The percentage of children who underwent adeno-tonsillar surgery in paediatric units was higher as compared to general units, as far as concerns the overall number of operations performed. In southern Italy, the number of adeno-tonsillar interventions, in general, and of adeno-tonsillectomy, in particular, was higher compared to that in northern Italy. Results of the present study suggest that environmental factors, cultural issues and local health demands, may influence indications and, therefore, the different incidence of the operations under consideration in the units taking part in the investigation.

Optimization of HAART with genetic algorithms and agent-based models of HIV infection

MOTIVATION

Highly Active AntiRetroviral Therapies (HAART) can prolong life significantly to people infected by HIV since, although unable to eradicate the virus, they are quite effective in maintaining control of the infection. However, since HAART have several undesirable side effects, it is considered useful to suspend the therapy according to a suitable schedule of Structured Therapeutic Interruptions (STI). In the present article we describe an application of genetic algorithms (GA) aimed at finding the optimal schedule for a HAART simulated with an agent-based model (ABM) of the immune system that reproduces the most significant features of the response of an organism to the HIV-1 infection.

RESULTS

The genetic algorithm helps in finding an optimal therapeutic schedule that maximizes immune restoration, minimizes the viral count and, through appropriate interruptions of the therapy, minimizes the dose of drug administered to the simulated patient. To validate the efficacy of the therapy that the genetic algorithm indicates as optimal, we ran simulations of opportunistic diseases and found that the selected therapy shows the best survival curve among the different simulated control groups.

AVAILABILITY

A version of the C-ImmSim simulator is available at http://www.iac.cnr.it/~filippo/c-ImmSim.html

DC13PC bilayers from anomalous swelling to main transition: An X-ray scattering investigation

We have performed small-angle (SAXS) and wide-angle X-ray scattering (WAXS) measurements on the lamellar phase and on large unilamellar vesicles (LUVs) of DC(13)PC in the temperature range corresponding to the anomalous swelling regime of multibilayer systems, adjacent to the chain melting transition, and across the transition. Our SAXS measurements indicate that on cooling from the L(alpha) phase, a uniform progressive swelling of the lamellar system to anomalous distances, starting approximately 2 degrees C above the main transition, is followed by a region of coexistence, covering the width of the transition ( approximately 0.6 degrees C). Across the transition region, a progressively increasing volume fraction of gel phase with a constant P (beta') interlamellar distance coexists with a decreasing amount of nongel phase that keeps on swelling to longer distances. Along both the swelling and the transition regions, anomalies in the specific heat are observed revealing a two-step process. Simultaneous WAXS experiments show a progressive "density" increase along the swelling region, constituting a direct spectroscopic evidence of an "evolving membrane" approaching the transition in a bulk real system. Calorimetric and densitometric measurements on LUVs are also presented, together with WAXS results, that show the existence of a double step main transition in a single component nanosized closed bilayer.

Clinical management of cutaneous toxicity of anti-EGFR agents

Cutaneous toxicity is the most evident adverse effect of epidermal growth factor receptor (EGFR) inhibitors because of the specific role played by EGFR in skin biophysiology. Dermatological adverse reactions, mainly folliculocentric, have been widely reported in the literature. However, the mechanism of these reactions is not well defined and their management is still a matter of debate. In this paper keratinocyte differentiation, activation and pathways regulating gene expression are reviewed in order to improve the understanding of adverse skin reactions and obtain success in their management. The authors had the opportunity to treat skin reactions induced by cetuximab in a cohort of patients affected by metastatic colorectal carcinoma. The aims of this clinical approach were to control the signs and symptoms of skin toxicity in order to avoid delay in cancer therapy and to use nondrug agents for the treatment of drug-induced skin reactions.

Analysis of vaccine’s schedules using models

We present a further, yet important, step in applying Catania Mouse Model & simulator (SimTriplex) of immune system response to vaccination. In particular we show that, as immune response can induce toxicity, one can calibrate the vaccine administrations in such a way to avoid toxicity effects, keeping immunoprevention from cancer. This result increases the model's potential applications.

[The treatment of acute recurrent pharyngotonsillitis]

AIM OF THE STUDY

In paediatric patients, recurrent febrile pharyngo-tonsillitis is usually due to chronic inflammation of the tonsils and/or adenoids: these episodes are often associated with other clinical manifestations (respiratory obstruction of naso-pharyngeal origin; auricular inflammation, especially effusive otitis media and acute otitis media; streptococcal beta-haemolytic Group A (SBEGA) infection, causing a distant disorder of varying severity and which may, therefore, give rise to serious pathological conditions). A retrospective multicentric investigation has, therefore, been carried out in order not only to further elaborate findings emerging from earlier studies, performed in other countries, in which random methods were used, but also to focus on: 1. the possible association of these clinical manifestations with recurrent febrile pharyngo-tonsillar inflammation in relation to frequency of the condition; 2. results obtained with adenoidectomy or with adeno-tonsillectomy, referring to the overall clinical outcome of the pathological condition, bearing in mind data emerging from the control groups, submitted to strict follow-up, associated with any medical treatment deemed necessary.

MATERIAL AND METHODS

The study population comprised 692 patients (394 male, 298 female), age range 2-11 years and with a minimum follow-up of 2 years. Considering the clinical manifestations emerging from the case history, the following two investigations were carried out: 1. the first, on 501 patients, all previously submitted to adeno-tonsillectomy in whom the recurrent febrile pharyngo-tonsillar inflammation had occurred, respectively > 4 or < or = 4 episodes during the last 12 months; 2. the second, on 455 patients in whom recurrent febrile pharyngo-tonsillar inflammation, in the 12 months prior to the beginning of the study, had been < or = 4 episodes: in 264 cases, adeno-tonsillectomy was carried out; in 144, adenoidectomy; 47 children were studied as controls and, therefore, submitted to watchful waiting. The results obtained were statistically analysed by chi2 and Fisher test: a "p" value of < 0.05 was considered statistically significant.

RESULTS

The first investigation showed that all symptomatological manifestations considered were resolved following adeno-tonsillectomy, in a significantly high percentage of cases (recurrent febrile pharyngo-tonsillar in flammation: 91.8%; naso-pharyngeal respiratory obstruction: 92.2%; pathological ASO titre: 69.8%; distant disorders probably due to SBEGA: 76%; effusive otitis media: 76%; acute recurrent otitis media: 87.5%). The most interesting clinical findings obtained can be summarized as follows: naso-pharyngeal respiratory obstruction is a frequent finding; the incidence is statistically higher in cases in which recurrent febrile pharyngo-tonsillar inflammation is less frequent (p < 0.05): in these patients, this is an important pathological manifestation indicating the need for surgery; the higher incidence is associated with at significant finding of pathological auricular processes; the percentages of recovery for naso-pharyngeal respiratory obstruction are statistically greater in the group of patients in whom the recurrent febrile pharyngo-tonsillar inflammation is more frequent: an identical result is found in patients with the effusive form of otitis media and in those with recurrent acute otitis media; a pathological ASO titre is more frequently found, the difference being statistically significant (p < 0.05), in the group of patients with more frequent recurrent febrile pharyngo-tonsillar inflammation, albeit this factor does not affect the percentage of recovery; also the favourable evolution and recovery of clinical distant manifestations, related to streptococcal beta-haemolytic Group A infection, are correlated with the return to normal of the ASO titre. The second investigation demonstrated the efficacy of surgical treatment, adeno-tonsillectomy and adenoidectomy, in all the clinical manifestations studied, the possibility of achieving resolution of recurrent febrile pharyngo-tonsillar inflammation even in the control subjects submitted to medical treatment, but also the lack of success, in the latter, as far as concerns naso-pharygeal respiratory obstruction, the pathological ASO titre and the inflammatory auricular processes.

CONCLUSIONS

The present investigations confirm previous observations emerging from randomized clinical studies, regarding the possibility to achieve valid prevention of recurrent febrile pharyngo-tonsillar inflammation, also in a large percentage of control patients submitted to watchful waiting; these investigations, however, also demonstrated that, in the control group, the percentage of subjects in whom recovery of other symptoms was achieved was very low compared to that in the groups submitted to surgery. In other words, clearly emerges as far as concerns the overall symptomatological picture of the patients, the efficacy of the surgical treatment, but also the lack of success of the medical treatments in all clinical manifestations associated with recurrent febrile inflammations. Therefore, it is necessary to select and advise the most suitable treatment strategy, not in relation to the Guidelines elaborated on the basis of results emerging from statistical research, that, due to the intrinsic methodology limits cannot be applied to all cases in an acritical fashion, but in relationship to the specific clinical picture of each individual patient.

[Acute recurrent pharyngotonsillitis and otitis media]

BACKGROUND

In the more recent randomized clinical studies, the surgical procedures adopted (adenoidectomy and adeno-tonsillectomy) for the treatment of the effusive and the acute recurrent forms of otitis media have generally shown a relatively modest and not persistent efficacy. It should be pointed out, however, that the cases studied displayed no clinical elements suggesting the existence of any aetio-pathogenic relationship between the auricular inflammation and a possible pathological disorder localized in the tonsils and/or adenoids.

AIM OF THE STUDY

The present investigation aimed to establish: a) the frequency with which the two forms of tympanic inflammation, under study, were detected in children with recurrent febrile pharyngo-tonsillar inflammation, also considering the possible presence of naso-pharyngeal respiratory obstruction and the severity of these two pathological manifestations; b) in relationship to these parameters, what might be the outcome with respect to the pathological auricular processes following surgical treatment of the pharyngeal disorder (adeno-tonsillectomy or adenoidectomy) vs. watchful waiting, c) the possible advantages offered by ventilation tube, inserted during surgical treatment, in the prevention of the two forms of otitis media studied.

MATERIAL AND METHODS

This retrospective multi-centre investigation involved 678 subjects (388 male, 290 female), age range 2 - 11 years: all subjects were followed-up for a minimum period of 2 years. Patients in this study population were submitted to 3 groups of investigations: a) in the first (487 children submitted to adeno-tonsillectomy), the study population was subdivided into 2 groups according to the frequency of the complaints of febrile pharyngo-tonsillar inflammation reported during the previous 12 months (> 4 or < or = 4); b) in the second (443 children with recurrent febrile pharyngo-tonsillar inflammation during the previous 12 months < or = 4), three groups of cases were compared; in the 1st (252 cases), patients were submitted to adeno-tonsillectomy; in the 2nd (144 subjects), adenoidectomy was carried out; in the 3rd (47 cases), the watchful waiting approach was adopted; c) in the third (193 cases, with both pathological auricular manifestations), patients were submitted to adeno-tonsillectomy (119 cases) or to adenoidectomy 74 cases); during surgery, ventilation tube was applied bilaterally in 61 cases, while 132 patients formed the control group. The results obtained were statistically analysed by chi2 and Fisher test: a "p" value of < 0.05 was considered statistically significant.

RESULTS

The first investigation showed: a) the incidence of cases with auricular disorders was greater in the group presenting recurrent febrile pharyngo-tonsillar inflammation < or = 4 (effusive otitis media: p < 0.05); in this group, the presence of cases with naso-pharyngeal respiratory obstruction was statistically greater (p < 0.05); b) the number of cases in which the pathological auricular process was resolved following adeno-tonsillectomy, appeared high (effusive otitis media: 136/179 = 76%; acute recurrent otitis media: 189/216 = 87.5%), not unlike the percentage of patients with positive results on recurrent febrile pharyngo-tonsillar inflammation and on naso-pharyngeal respiratory obstruction (91.6% and 92.4%, respectively); c) the percentages of recovery, for auricular disorders, were significantly higher in the group presenting more frequent recurrent febrile pharyngo-tonsillar inflammation, i.e. > 4 (p < 0.05); in this group, also the incidence of cases, in which the naso-pharyngeal respiratory obstruction was resolved, was greater. The second investigation demonstrated, in the groups in which surgical treatment was carried out, compared to controls: a) a significantly greater percentage of cases achieving recovery, for both parameters (p < 0.05); as far as concerns the effusive form of otitis media, a total of 72 (67.3%) subjects were cured following adeno-tonsillectomy; 67 (81.7%), following adenoidectomy; in acute recurrent otitis media, the subjects achieving recovery were; for adeno-tonsillectomy, 97 (82.2%); for adenoidectomy; 85 (81.7%); b) in the subjects in whom, following surgical treatment, the inflammatory auricular disorder was resolved, it was generally found that recovery had been achieved not only for the recurrent febrile pharyngo-tonsillar inflammation but also for the naso-pharyngeal respiratory obstruction; c) in the controls, the results appeared to be significantly less satisfactory (< 0.001); together with the lack of success in the watchful waiting approach, as far as concerns auricular disorders, we found, likewise, a significant lack of efficacy (p < 0.001) of this treatment in the management of naso-pharyngeal respiratory obstruction (5/35 cases cured: 14.3%). The third investigation showed that the application of the ventilation tube during adeno-tonsillectomy or adenoidectomy did not lead to any improvement in the results; indeed, the percent recovery of the pathological tympanic processes was significantly greater (p < 0.05) in those subjects in whom transtympanic drainage had not been adopted.

CONCLUSIONS

The results of these investigations reveal a clear relationship between the naso-pharyngeal respiratory obstruction and the pathological auricular processes in subjects with episodes of recurrent febrile pharyngo-tonsillar inflammation. These results also demonstrate that adeno-tonsillectomy and/or adenoidectomy are able to resolve the auricular inflammatory manifestations in a very large percentage of cases. These data are apparently in contrast with those described in recent reports related to randomised investigations. In effect, the two groups of investigations had different aims: the studies carried out according to a randomised approach were performed on study populations in which the findings of pathological auricular manifestations were not linked by the demonstration of a correlation with possible adenoid or adeno-tonsillar inflammation; the present study, on the other hand, was performed on patients in whom the auricular disorder was part of the clinical picture of recurrent febrile pharyngo-tonsillar inflammation. Therefore we believe that each of these study methods has precise possibilities, but also limitations; thus, one should not exclude the other, but rather be integrated.

Formation of self-organized nanoparticles by lecithin/chitosan ionic interaction

In this work the production of auto-assembled nanoparticles obtained by the mixing of chitosan and lecithin is presented. The size and surface charge of the nanoparticles were studied as function of the weight ratio between components, the viscosity of the polysaccharide and the pH of the colloidal suspension. In order to elucidate the structure of nanoparticles, micro-FT-IR and elastic neutron scattering experiments have been performed. Results evidenced a strong electrostatic interaction between components and a structure that is neither that of homogeneous spheres nor of coated unilamellar vesicles. Preliminary encapsulation experiments with progesterone, as model lipophilic drug, showed good encapsulation efficiencies.

Modeling and simulation of cancer immunoprevention vaccine

We present an in silico model that simulates the immune system responses to tumor cells in naive and vaccinated mice. We have demonstrated the ability of this model to accurately reproduce the experimental results.

MOTIVATION

In vivo experiments on HER-2/neu mice have shown the effectiveness of Triplex vaccine in the protection of mice from mammary carcinoma. Full protection was conferred using chronic (prophylactic) vaccination protocol while therapeutic vaccination was less efficient. Our in silico model was able to closely reproduce the effects of various vaccination protocols. This model is the first step towards the development of in silico experiments searching for optimal vaccination protocols.

RESULTS

In silico experiments carried out on two large statistical samples of virtual mice showed very good agreements with in vivo experiments for all experimental vaccination protocols. They also show, as supported by in vivo experiments, that the humoral response is fundamental in controlling the tumor growth and therefore suggest the selection and timing of experiments for measuring the activity of T cells.

CONTACT

francesco@dmi.unict.it

SUPPLEMENTARY INFORMATION

http://www.dmi.unict.it/CIG/suppdata_bioinf.html.

CO2 Laser Treatment of Bilateral Vocal Cord Paralysis in Adduction

This study presents results obtained from 83 patients with bilateral vocal cord paralysis in adduction treated between 1982 to 2001, with CO(2) laser microlaryngoscopy. In relation to the different types of surgery followed, three distinct treatment groups were included: group 1 (1982-1984) included 5 patients treated with vaporization of the vocal process of the arytenoid and the homolateral posterior third of the true vocal cord. Group 2 (1983-1990) contained 19 patients who were treated with arytenoidectomy and removal of the homolateral posterior half of the true vocal cord and group 3 (1990-2001), including 59 patients who were treated with arytenoidectomy and removal of the homolateral posterior half or two thirds of both the true and false vocal cord. Functional results were assessed by means of spirometry, spectrography and aerophonic examinations performed at 5, 90, 180, and 240 days postoperatively. The results show that removal of the posterior third of the true vocal cord and false vocal cord, combined with arytenoidectomy, is the surgical treatment of choice to resolve respiratory insufficiency in these patients.

[Comparative compositional mapping of chicken and quail chromosomes]

The distribution of various isochore families on mitotic chromosomes of domestic chicken and Japanese quail was studied by the method of fluorescence in situ DNA--DNA hybridization (FISH). DNA of various isochore families was shown to be distributed irregularly and similarly on chromosomes of domestic chicken and Japanese quail. The GC-rich isochore families (H2, H3, and H4) hybridized mainly to microchromosomes and a majority of macrochromosome telomeric regions. In chicken, an intense fluorescence was also in a structural heterochromatin region of the Z chromosome long arm. In some regions of the quail macrochromosome arms, hybridization was also with isochore families H3 and H4. On macrochromosomes of both species, the pattern of hybridization with isochores of the H2 and H3 families resembled R-banding. The light isochores (L1 and L2 families) are mostly detected within macrochromosome internal regions corresponding to G bands, whereas microchromosomes lack light isochores. Although mammalian and avian karyotypes differ significantly in organization, the isochore distribution in genomes of these two lineages of the warm-blooded animals is similar in principle. On macrochromosomes of the two avian species studied, a pattern of isochore distribution resembled that of mammalian chromosomes. The main specific feature of the avian genome, a great number of microchromosomes (about 30% of the genome), determines a compositional specialization of the latter. This suggests the existence of not only structural but also functional compartmentalization of the avian genome.

Compositional mapping of chicken chromosomes and identification of the gene-richest regions

'Compositional chromosomal mapping', namely the assessment of the GC level of chromosomal bands, led to the identification, in the human chromosomes, of the GC-richest H3+ bands and of the GC-poorest L1+ bands, which were so called on the basis of the isochore family predominantly present in the bands. The isochore organization of the avian genome is very similar to those of most mammals, the only difference being the presence of an additional, GC-richest, H4 isochore family. In contrast, the avian karyotypes are very different from those of mammals, being characterized, in most species, by few macrochromosomes and by a large number of microchromosomes. The 'compositional mapping' of chicken mitotic and meiotic chromosomes by in-situ hybridization of isochore families showed that the chicken GC-richest isochores are localized not only on a large number of microchromosomes but also on almost all telomeric bands of macrochromosomes. On the other hand, the GC-poorest isochores are generally localized on the internal regions of macrochromosomes and are almost absent in microchromosomes. Thus, the distinct localization of the GC-richest and the GC-poorest bands observed on human chromosomes appears to be a general feature of chromosomes from warm-blooded vertebrates.